The invention relates generally to the field of network communications. More specifically, the invention relates to a system and method for switching communications traffic at a node in a network.
Some techniques for switching communications traffic at a node in a network are known. As illustrated in FIG. 1, a representative switch or router at a node in a network includes a chassis 150 populated by line cards 105, 110, 115, 120, 135, and 140, primary switch fabric card 125, back-up switch fabric card 130, and a controller card 145. Some known routers also use a back-up controller card (not shown).
Data traffic is received in a line card (e.g., 105, 110, 115, 120, 135, 140), and switched through the primary switch fabric card 125. The primary switch fabric card 125 and back-up switch fabric card 130 are configured to redirect network traffic (data) to one or more line cards. In turn, the line cards transmit the network traffic to a next or final destination node on the network. The primary switch fabric card 125 and back-up switch fabric card 130 can include, for example, crossbars or shared memory devices. The line cards 105, 110, 115, 120, 135, and 140 are used for buffering network traffic on either side of the switch fabric, and for performing other functions. Line cards typically serve both ingress and egress functions (i.e., for incoming and outgoing traffic, respectively).
Router communications can be separated into three categories: management plane; control plane; and data plane communications. The management plane is an interface between functions external to the router (e.g., network servers or clients) and the router controller(s). For example, chassis configuration parameters that are derived from Service Level Agreements (SLA's) are communicated to the router on the management plane. The control plane uses local signaling protocols or other messages to control the resources of a router in accordance with the specified configuration. In one respect, the control plane can be used to provision resources in the router in accordance with the SLA's. The data plane carries network data that is being redirected (or forwarded) by the router to the next or final destination node on the network.
Known systems and methods for switching communications traffic have various disadvantageous. For example, in provisioning resources in the control plane, some known systems check for the availability of resources in the line cards, but do not check for the availability of resources in the switch fabric. As a consequence, the potential for congestion in the switch fabric is high, especially during data traffic bursts. Such congestion may lead to undesirable increases in latency. Moreover, inadequate provisioning may result in a loss of data in the router. Either result compromises the ability to provide a Quality of Service (QoS) that is in accordance with the SLA's.
Therefore, a need exists for a system and method to provide more robust bandwidth management in a network switch or router.